hazardous materials glossary - uab...alkali the hydroxides and carbonates of the alkali metals and...

Hazardous Materials Glossary

Hazardous Materials

Glossary Last Updated: 06/05/2017

Absorbed Dose

The amount of a chemical that enters the body of an exposed organism.

Absorption

1. The passing of a substance into the circulatory system of the body. Also used specifically to refer to

entry of toxicants through the skin.

2. The uptake of water or dissolved chemicals by a cell or an organism (as tree roots absorb dissolved

nutrients in soil.)

3. The penetration of atoms, ions, or molecules into the bulk mass of a substance.

Accident Site

The location of an unexpected occurrence, failure or loss, either at a plant or along a transportation route,

resulting in a release of hazardous materials.

Acclimatization

The physiological and behavioral adjustments of an organism to changes in its environment.

ACGIH

American Conference of Governmental Industrial Hygienists is an organization of professional personnel in

governmental agencies or educational institutions who are employed in occupational safety and health

programs.

Acid

Any chemical which undergoes dissociation in water with the formation of hydrogen ions. Acids turn litmus

paper red and have pH values of 0 to 6. They may cause severe skin burns.

Acid Deposition

A complex chemical and atmospheric phenomenon that occurs when emissions of sulfur and nitrogen

compounds and other substances are transformed by chemical processes in the atmosphere, often far from the

original sources, and then deposited on earth in either wet or dry form. The wet forms, popularly called "acid

rain," can fall as rain, snow, or fog. The dry forms are acidic gases or particulates.

Acidic

The condition of water or soil that contains a sufficient amount of acid substances to lower the pH below 7.0


Hazardous Materials


Activated Carbon

A highly adsorbent form of carbon used to remove odors and toxic substances from liquid or gaseous

emissions. In waste treatment it is used to remove dissolved organic matter from waste water. It is also used in

motor vehicle evaporative control systems.

Activator

A chemical added to a pesticide to increase its activity.

Active Ingredient

In any pesticide product, the component that kills, or otherwise controls, target pests. Pesticides are regulated

primarily on the basis of active ingredients.

Acute Effect

Adverse effect on a human or animal which has severe symptoms developing rapidly and coming quickly to a

crisis. Also see chronic effect.

Acute Exposure

1. An exposure to a toxic substance which occurs in a short or single time period.

2. A single exposure to a toxic substance which results in severe biological harm or death. Acute

exposures are usually characterized as lasting no longer than a day, as compared to longer, continuing

exposure over a period of time.

Acute Toxicity

Any poisonous effect produced by a single short-term exposure. The LDW of a substance (the lethal dose at

which 50 percent of test animals succumb to the toxicity of the chemicals) is typically used as a measure of its

acute toxicity.

Adaptation

Changes in an organism's structure or habits that help it adjust to its surroundings.

Additive Effect

A biological response to exposure to multiple chemicals which is equal to the sum of the effects of the

individual agents.

Administrative Order

A legal document signed by EPA directing an individual, business, or other entity to take corrective action or

refrain from an activity. It describes the violations and actions to be taken, and can be enforced in court. Such

orders may be issued, for example, as a result of an administrative complaint whereby the respondent is

ordered to pay a penalty for violations of a statute.


Hazardous Materials


Adsorption

The bonding of chemicals to soil particles or other surfaces.

Aerosol

A solid particle or liquid droplet suspended in air. An aerosol is larger than a molecule and can be filtered

from the air (for example: smoke or fog).

Affected Public

The people who live and/or work near a hazardous waste site.

Airborne Particulates

Total suspended particulate matter found in the atmosphere as solid particles or liquid droplets. Chemical

composition of particulates varies widely, depending on location and time of year. Airborne particulates

include – windblown dust, emissions from industrial processes, smoke from the burning of wood and coal,

and motor vehicle or non-road engine exhausts, exhaust of motor vehicles.

Alkali

The hydroxides and carbonates of the alkali metals and alkaline earth metals. They neutralize acids, impart a

soapy feel to aqueous solutions and are the commonest cause of occupational dermatitis.

Alkaline

The condition of water or soil which contains a sufficient amount of alkali substance to raise the pH above

7.0.

Alkalinity

The capacity of water to neutralize acids.

Anaerobic

1. A life or process that occurs in, or is not destroyed by, the absence of oxygen.

2. Able to live, grow, or take place where free oxygen is not present.

Anoxic

Total deprivation of oxygen.

Antagonism

The situation in which two chemicals interfere with each other’s actions, or one chemical interferes with the

action of the other.

Aqueous

Something made up of, similar to, or containing water; watery.


Hazardous Materials


Arsenicals

Pesticides containing arsenic.

Asbestos

A mineral fiber that can pollute air or water and cause cancer or asbestosis when inhaled. EPA has banned or

severely restricted its use in manufacturing and construction.

Asbestosis

A disease associated with inhalation of asbestos fibers. The disease makes breathing progressively more

difficult and can be fatal.

Assay

A test for a particular chemical or effect.

Bacteria

1. (Singular -- bacterium) Microscopic living organisms that can aid in pollution control by metabolizing

organic matter in sewage, oil spills or other pollutants. However, bacteria in soil, water or air can also

cause human, animal and plant health problems.

2. Unicellular microorganisms that exist either as free-living organisms or as parasites and have a broad

range of biochemical, and often pathogenic, properties. Bacteria can be grouped by form into five

general categories -- cocci (spherical), bacilli (rod-shaped), vibrio (curved rod-shaped), spirilla

(spiral), and filamentous (thread-like).

Base

A water soluble compound capable of reacting with an acid to form a salt by releasing an un- shared pair of

electrons to the acid or by receiving a proton from the acid.

Benign

Not recurrent or not tending to progress.

Beryllium

An airborne metal hazardous to human health when inhaled. It is discharged by machine shops, ceramic and

propellant plants, and foundries.


Hazardous Materials


Bioassay

1. A method used to determine the toxicity of specific chemical contaminants. A number of individuals

of a sensitive species are placed in water containing specific concentrations of the contaminant for a

specified period of time.

2. Study of living organisms to measure the effect of a substance, factor, or condition by comparing

before-and-after exposure or other data.

3. A determination of the concentration of a substance in a human body by an analysis of urine, feces,

blood, bone, or tissue.

Biodegradable

1. Capable of being broken down into individual components by the action of living things.

2. Capable of decomposing rapidly under natural conditions.

Biodiversity

Refers to the variety and variability among living organisms and the ecological complexes in which they

occur. Diversity can be defined as the number of different items and their relative frequencies. For biological

diversity, these items are organized at many levels, ranging from complete ecosystems to the biochemical

structures that are the molecular basis of heredity. Thus, the term encompasses different ecosystem, species,

and genes.

Biologicals

Vaccines, cultures and other preparations made from living organisms and their products, intended for use in

diagnosing, immunizing, or treating humans or animals, or in related research.

Biopsy

Removal and examination of tissue from the living body.

Biotechnology

Techniques that use living organisms or parts of organisms to produce a variety of products (from medicines

to industrial enzymes) to improve plants or animals or to develop microorganisms to remove toxics from

bodies of water, or act as pesticides.

Blood Products

Any product derived from human blood, including but not limited to blood plasma, platelets, red or white

corpuscles, and derived licensed products such as interferon.


Hazardous Materials


Boiling Point

The temperature at which a liquid changes to a vapor state at a given pressure. The boiling point usually

expressed in degrees Fahrenheit at sea level pressure (760mm Hg, or one atmosphere). For mixtures, the

initial boiling point or the boiling range may be given. Flammable materials with low boiling points generally

present special fire hazards. Some approximate boiling points:

Propane -44 F

Anhydrous Ammonia -28 F

Butane 31 F

Gasoline 100 F

Allyl Chloride 113 F

Ethylene Glycol 387 F

Boiling point is the temperature at which a component's vapor pressure equals atmospheric pressure. It is a

relative indicator of volatility and generally increases with increasing molecular weight.

Brackish

Mixed fresh and salt water.

Bulky Waste

Large items of waste materials, such as appliances, furniture, large auto parts, trees, stumps.

By-product

Material, other than the principal product, generated as a consequence of an industrial process.

C

Centigrade, a unit of temperature.

C or Ceiling

The maximum allowable human exposure limit for an airborne substance which is not to be exceeded even

momentarily. Also see PEL and TLV.

Cadmium (Cd)

A heavy metal element that accumulates in the environment.

Carbon Monoxide (CO)

A colorless, odorless, poisonous gas produced by incomplete fossil fuel combustion.

Carcinogenicity

The ability to produce cancer.


Hazardous Materials


Carcinogen

A substance or agent capable of causing or producing cancer in mammals, including humans. A chemical is

considered to be a carcinogen if:

1. It has been evaluated by the International Agency for Research on Cancer (IARC) and found to be a

carcinogen or potential carcinogen; or

2. It is listed as a carcinogen or potential carcinogen in the Annual Report on Carcinogens published by

the National Toxicology Program (NTP) (latest edition); or

3. It is regulated by OSHA as a carcinogen.

Carcinoma

A malignant tumor. A form of cancer.

Carrier

The inert liquid or solid material added to an active ingredient in a pesticide.

Catalyst

A substance that changes the speed or yield of a chemical reaction without being consumed or chemically

changed by the chemical reaction.

Caustic

See alkali.

Cells

1. In solid waste disposal, holes where waste is dumped, compacted, and covered with layers of dirt on a

daily basis.

2. The smallest structural part of living matter capable of functioning as an independent unit.

Central Nervous System

The brain and spinal cord. These organs supervise and coordinate the activity of the entire nervous system.

Sensory impulses are transmitted into the central nervous system, and motor impulses are transmitted out.

Central Nervous System Depressants

Toxicants that deaden the central nervous system (CNS), diminishing sensation.

CFR

Code of Federal Regulations. A collection of the regulations that have been promulgated under United States

law.


Hazardous Materials


Chemical

Any element, chemical compound or mixture of elements and/or compounds where chemical(s) are or

distributed.

Chemical Oxygen Demand (COD)

A measure of the oxygen required to oxidize all compounds, both organic and inorganic, in water.

Chlorination

The application of chlorine to drinking water, sewage, or industrial waste to disinfect or to oxidize undesirable

compounds.

Chronic Effect

An adverse effect on a human or animal in which symptoms recur frequently or develop slowly over a long

period of time.

Chronic Exposure

Process by which small amounts of toxic substances are taken into the body over an extended period.

Chronic Toxicity

The capacity of a substance to cause long-term poisonous human health effects. (See -- acute toxicity.)

Clean Fuels

Blends or substitutes for gasoline fuels, including compressed natural gas, methanol, ethanol, liquified

petroleum gas, and others.

Cleanup

Actions taken to deal with a release or threat of release of a hazardous substance that could affect humans

and/or the environment. The term "cleanup" is sometimes used interchangeably with the terms remedial

action, removal action, response action, or corrective action.

Coagulation

Clumping of particles in wastewater to settle out impurities, often induced by chemicals such as lime, alum,

and iron salts.

Combustion

1. Burning, or rapid oxidation, accompanied by release of energy in the form of heat and light. A basic

cause of air pollution.

2. Refers to controlled burning of waste, in which heat chemically alters organic compounds, converting

into stable inorganics such as carbon dioxide and water.


Hazardous Materials


Commercial Waste

All solid waste emanating from business establishments such as stores, markets, office buildings, restaurants,

shopping centers, and theaters.

Conductivity

1. A coefficient of proportionality describing the rate at which a fluid (e.g., water or gas) can move

through a permeable medium. Conductivity is a function of both the intrinsic permeability of the

porous medium and the kinematic viscosity of the fluid which flows through it.

2. A measure of the ability of a solution to carry an electrical current.

Conservation

Preserving and renewing, when possible, human and natural resources. The use, protection, and improvement

of natural resources according to principles that will assure their highest economic or social benefits.

Constituent

An essential part or component of a system or group (e.g., an ingredient of a chemical mixture). For instance,

benzene is one constituent of gasoline.

Contaminant

Any physical, chemical, biological, or radiological substance or matter that has an adverse affect on air, water,

or soil.

Contamination

Introduction into water, air and soil of microorganisms, chemicals, toxic substances, wastes, or wastewater in

a concentration that makes the medium unfit for its next intended use. Also applies to surfaces of objects and

buildings, and various household and agricultural use products.

Contingency Plan

A document setting out an organized, planned, and coordinated course of action to be followed in case of a

fire, explosion, or other accident that releases toxic chemicals, hazardous waste, or radioactive materials that

threaten human health or the environment. (See -- National Oil and Hazardous Substances Contingency Plan.)

Core

The uranium-containing heart of a nuclear reactor, where energy is released.

Corrosion

The dissolution and wearing away of metal caused by a chemical reaction such as between water and the

pipes, chemicals touching a metal surface, or contact between two metals.


Hazardous Materials


Corrosive

1. A chemical that destroys or irreversibly alters living tissue by direct chemical action at the site of

contact.

2. A chemical agent that reacts with the surface of a material causing it to deteriorate or wear away.

Criteria

Descriptive factors taken into account by EPA in setting standards for various pollutants. These factors are

used to determine limits on allowable concentration levels, and to limit the number of violations per year.

When issued by EPA, the criteria provide guidance to the states on how to establish their standards.

Decay Products

Degraded radioactive materials, often referred to as "daughters" or "progeny"; radon decay products of most

concern from a public health standpoint are polonium-214 and polonium-218.

Dechlorination

Removal of chlorine from a substance by chemically replacing it with hydrogen or hydroxide ions in order to

detoxify a substances.

Decomposition

The breakdown of matter by bacteria and fungi, changing the chemical makeup and physical appearance of

materials.

Decontamination

1. The process of removing or neutralizing contaminants that have accumulated on personnel and

equipment. This process is critical to health and safety at hazardous waste incidents.

2. Removal of harmful substances such as noxious chemicals, harmful bacteria or other organisms, or

radioactive material from exposed individuals, rooms and furnishings in buildings, or the exterior

environment.

Density

A measure of how heavy a solid, liquid, or gas is for its size. The amount of mass per unit volume.

Dermal Toxicity

The ability of a pesticide or toxic chemical to poison people or animals by contact with the skin. (See --

contact pesticide.)

Detergent

Synthetic washing agent that helps to remove dirt and oil. Some contain compounds which kill useful bacteria

and encourage algae growth when they are in wastewater that reaches receiving waters.


Hazardous Materials


Development Effects

Adverse effects such as altered growth, structural abnormality, functional deficiency, or death observed in a

developing organism.

Diffusion

1. The movement of suspended or dissolved particles from a more concentrated to a less concentrated

area. The process tends to distribute the particles more uniformly.

2. The process by which molecules in a single phase equilibrate to a zero concentration gradient by

random molecular motion (Brownian motion). The flux of molecules is from regions of high

concentration to low concentration and is governed by Fick's Second Law.

Digestion

The biochemical decomposition of organic matter, resulting in partial gasification, liquefaction, and

mineralization of pollutants.

Diluent

Any liquid or solid material used to dilute or carry an active ingredient.

Dioxin

Any of a family of compounds known chemically as dibenzo-p-dioxins. Concern about them arises from their

potential toxicity and contaminants in commercial products. Tests on laboratory animals indicate that it is one

of the more toxic man-made compounds.

Discharge

Flow of surface water in a stream or canal or the outflow of ground water from a flowing artesian well, ditch,

or spring. Can also apply to discharge of liquid effluent from a facility or of chemical emissions into the air

through designated venting mechanisms.

Disinfectant

A chemical or physical process that kills pathogenic organisms in water. Chlorine is often used to disinfect

sewage treatment effluent, water supplies, wells, and swimming pools.

Dispersion

The process by which a substance or chemical spreads and dilutes in flowing groundwater or soil gas.

Disposal

Final placement or destruction of toxic, radioactive, or other wastes; surplus or banned pesticides or other

chemicals; polluted soils; and drums containing hazardous materials from removal actions or accidental

releases. Disposal may be accomplished through use of approved secure landfills, surface impoundments, land

farming, deep-well injection, ocean dumping, or incineration.


Hazardous Materials


Distillation

The act of purifying liquids through boiling, so that the steam condenses to a pure liquid and the pollutants

remain in a concentrated residue.

Dosage/Dose

The actual quantity of a chemical administered to an organism or to which it is exposed.

Dose Equivalent

The product of the absorbed does from ionizing radiation and such factors as account for biological

differences due to the type of radiation and its distribution in the body as specified by the International

Commission on Radiological Units and Measurements.

Dose Response

How a biological organism's response to a toxic substance quantitatively shifts as its overall exposure to the

substance changes (e.g., a small dose of carbon monoxide may cause drowsiness; a large dose can be fatal.)

Ecology

The relationship of living things to one another and their environment, or the study of such relationships.

Ecosystem

The interacting system of a biological community and its non-living environmental surroundings.

Emission

Pollution discharged into the atmosphere from smokestacks, other vents, and surface areas of commercial or

industrial facilities; from residential chimneys; and from motor vehicle, locomotive, or aircraft exhausts.

Empirical

Relying upon or gained from experiment or observation.

Encapsulation

The treatment of asbestos-containing material with a liquid that covers the surface with a protective coating or

embeds fibers in an adhesive matrix to prevent their release into the air.

Environment

The sum of all external conditions affecting the life, development and survival of an organism.

Environmental Exposure

Human exposure to pollutants originating from facility emissions. Threshold levels are not necessarily

surpassed, but low level chronic pollutant exposure is one of the most common forms of environmental

exposure. (See -- Threshold Level.)


Hazardous Materials


Enzyme

1. Any of numerous proteins or conjugated proteins produced by living organisms and functioning as

biochemical catalysts.

2. A protein that a living organism uses in the process of degrading a specific compound. The protein

serves as a catalyst in the compound's biochemical transformation.

Epidemiology

Study of the distribution of disease, or other health-related states and events in human populations, as related

to age, sex, occupation, ethnic, and economic status in order to identify and alleviate health problems and

promote better health.

Equilibrium

In relation to radiation, the state at which the radioactivity of consecutive elements within a radioactive series

is neither increasing nor decreasing.

Erosion

The wearing away of land surface by wind or water, intensified by land-clearing practices related to farming,

residential or industrial development, road building, or logging.

Ethanol

An alternative automotive fuel derived from grain and corn; usually blended with gasoline to form gasohol.

Evaporation

The process by which a liquid enters the vapor (gas) phase.

Evaporation Rate

The rate at which a chemical changes into a vapor. A chemical that evaporates quickly can be a more

dangerous fire or health hazard.

Exposure

The amount of radiation or pollutant present in a given environment that represents a potential health threat to

living organisms.

Exposure Level

The amount (concentration) of a chemical at the absorptive surfaces of an organism.

Extremely Hazardous Substance (EHS)

Any one of over 300 hazardous chemicals on a list compiled by EPA to provide a focus for State and local

emergency planning activities.


Hazardous Materials


Extremely Hazardous Substances

Any of 406 chemicals identified by EPA as toxic, and listed under SARA Title III. The list is subject to

periodic revision.

Filtration

A treatment process, under the control of qualified operators, for removing solid (particulate) matter from

water by means of porous media such as sand or a man-made filter; often used to remove particles that

containing pathogens.

Floor Sweep

Capture of heavier-than-air gases that collect at floor level.

Flow Rate

The rate, expressed in gallons-or liters-per-hour, at which a fluid escapes from a hole or fissure in a tank. Such

measurements are also made of liquid waste, effluent, and surface water movement.

Fluoridation

The addition of a chemical to increase the concentration of fluoride ions drinking water to reduce the

incidence of tooth decay in children.

Fluorides

Gaseous, solid, or dissolved compounds containing fluorine that result from industrial processes. Excessive

amounts in food can lead to fluorosis.

Fluorocarbons (FCs)

Any of a number of organic compounds analogous to hydrocarbons in which one or more hydrogen atoms are

replaced by fluorine. Once used in the United States as a propellant for domestic aerosols, they are now found

mainly in coolants and some industrial processes. FCs containing chlorine are called chlorofluorocarbons

(CFCs). They are believed to be modifying the ozone layer in the stratosphere, thereby allowing more harmful

solar radiation to reach the Earth's surface.

Food Chain

A sequence of organisms, each of which uses the next, lower member of the sequence as a food source.

Formaldehyde

A colorless, pungent, and irritating gas, CH20, used chiefly as a disinfectant and preservative and in

synthesizing other compounds like resins.

Fume

Tiny particles trapped in vapor in a gas stream.


Hazardous Materials


Fungi

Singular -- Fungus) Molds, mildews, yeasts, mushrooms, and puffballs, a group organisms lacking in

chlorophyll (i.e., are not photosynthetic) and which are usually non-mobile, filamentous, and multicellular.

Some grow in soil, others attach themselves to decaying trees and other plants whence they obtain nutrients.

Some are pathogens, others stabilize sewage and digest composted waste. Along with bacteria, fungi are the

principal organisms responsible for the decomposition of carbon in the biosphere. Fungi have two ecological

advantages over bacteria -- (1) they can grow in low moisture areas, and (2) they can grow in low pH

environments.

Garbage

Animal and vegetable waste resulting from the handling, storage, sale, preparation, cooking, and serving of

foods.

Germicide

Any compound that kills disease-causing microorganisms.

Gray Water

Domestic wastewater composed of wash water from kitchen, bathroom, and laundry sinks, tubs, and washers.

Greenhouse Effect

The warming of the Earth's atmosphere attributed to a build-up of carbon dioxide or other gases; some

scientists think that this build-up allows the sun's rays to heat the Earth, while infra-red radiation makes the

atmosphere opaque to a counterbalancing loss of heat.

Ground Water

The supply of fresh water found beneath the Earth's surface, usually in aquifers, which supply wells and

springs. Because ground water is a major source of drinking water, there is growing concern over

contamination from leaching agricultural or industrial pollutants or leaking underground storage tanks.

Groundwater

The water contained in the pore spaces of saturated geologic media.

Half-Life

1. The time required for a pollutant to lose half its affect on the environment. For example, the

biochemical half-life of DDT in the environment is 15 years of Radium. 1,580 years.

2. The time required for half of the atoms of a radioactive element to undergo self-transmutation or

decay.

3. The time required for the elimination of one half a total dose from the body.


Hazardous Materials


Halon

Bromine-containing compounds with long atmospheric lifetimes whose breakdown in the stratosphere causes

depletion of ozone. Halons are used in fire-fighting.

Hard Water

Alkaline water containing dissolved salts that interfere with some industrial processes and prevent soap from

sudsing.

Hazard Class

A group of materials, as designated by the Department of Transportation, that share a common major

hazardous property such as radioactivity or flammability.

Hazard Communication Standard

An OSHA regulation that requires chemical manufacturers, suppliers, and importers to assess the hazards of

the chemicals that they make, supply, or import, and to inform employers, customers, and workers of these

hazards through MSDS sheets.

Hazard Evaluation

A component of risk evaluation that involves gathering and evaluating data on the types of health injury or

disease that may be produced by a chemical and on the conditions of exposure under which such health

effects are produced.

Hazard Identification

Determining if a chemical can cause adverse health effects in humans and what those affects might be.

Hazardous Chemical

An EPA designation for any hazardous material requiring an MSDS under OSHA's Hazard Communication

Standard. Such substances are capable of producing fires and explosions or adverse health effects like cancer

and dermatitis. Hazardous chemicals are distinct from hazardous waste.(See -- Hazardous Waste.)

Hazardous Ranking System

The principle screening tool used by EPA to evaluate risks to public health and the environment associated

with abandoned or uncontrolled hazardous waste sites. The HRS calculates a score based on the potential of

hazardous substances spreading from the site through the air, surface water, or ground water, and on other

factors such as density and proximity of human population. This score is the primary factor in deciding if the

site should be on the National Priorities List and, if so, what ranking it should have compared to other sites on

the list.


Hazardous Materials


Hazardous Substance

1. Any material that poses a threat to human health and- /or the environment. Typical hazardous

substances are toxic, corrosive, ignitable, explosive, or chemically reactive.

2. Any substance designated by EPA to be reported if a designated quantity of the substance is spilled in

the waters of the United States or if otherwise released into the environment.

Hazardous Waste

By-products of society that can pose a substantial or potential hazard to human health or the environment

when improperly managed. Possesses at least one of four characteristics (ignitability, corrosivity, reactivity,

or toxicity), or appears on special EPA lists.

Hazards Analysis

Procedures used to (1) identify potential sources of release of hazardous materials from fixed facilities or

transportation accidents; (2) determine the vulnerability of a geographical area to a release of hazardous

materials; and (3) compare hazards to determine which present greater or lesser risks to a community.

Hazards Identification

Providing information on which facilities have extremely hazardous substances, what those chemicals are,

and how much there is at each facility, how the chemicals are stored, and whether they are used at high

temperatures.

Health Education

A program of activities to promote health and provide information and training about hazardous substances in

the environment that will result in the reduction of exposure, illness, or disease. This program--both national

and site-specific in focus--includes diagnosis and treatment information for health care providers and

activities in communities to enable them to prevent or mitigate the health effects from exposure to hazardous

substances at hazardous waste sites.

Health Outcome Data

A major source of data for public health assessments. The identification, review, and evaluation of health

outcome parameters are interactive processes involving the health assessors, data source generators, and the

local community. Health outcome data are community specific and may be derived from databases at the

local, state, and national levels, as well as from data collected by private health care organizations and

professional institutions and associations. Databases to be considered include morbidity and mortality data,

birth statistics, medical records, tumor and disease registries, surveillance data, and previously conducted

health studies.

Heat Capacity

The quantity of energy that must be supplied to raise the temperature of a substance. For contaminated soils

heat capacity is the quantity of energy that must be added to the soil to volatilize organic components. The

typical range of heat capacity of soils is relatively narrow, therefore variations are not likely to have a major

impact on application of a thermal desorption process.


Hazardous Materials


Heavy Metals

Metallic elements with high atomic weights, e.g., mercury, chromium, cadmium, arsenic, and lead; can

damage living things at low concentrations and tend to accumulate in the food chain.

Herbicide

A chemical pesticide designed to control or destroy plants, weeds, or grasses.

Herbivore

An animal that feeds on plants.

Heterogeneous

Varying in structure or composition at different locations in space.

Homogeneous

Uniform in structure or composition at all locations in space.

Host

1. In genetics, the organism, typically a bacterium, into which a gene from another organism is

transplanted.

2. In medicine, an animal infected or parasitized by another organism.

Household Waste (Domestic Waste)

Solid waste, composed of garbage and rubbish, which normally originated in a private home or apartment

house. Domestic waste may contain a significant amount of toxic or hazardous waste.

Human Equivalent Dose

A dose which, when administered to humans, produces an effect equal to that produced by a dose in animals.

Human Health Risk

The likelihood that a given exposure or series of exposures may have or will damage the health of individuals.

Hydrocarbon

Chemical compounds composed only of carbon and hydrogen.

Hydrogen Peroxide

H2O2. Hydrogen peroxide is used to increase the dissolved oxygen content of groundwater to stimulate

aerobic biodegradation of organic contaminants. Hydrogen peroxide is infinitely soluble in water, but rapidly

dissociates to form a molecule of water [H2O] and one-half molecule of oxygen [O]. Dissolved oxygen

concentrations of greater than 1,000 mg/L are possible using hydrogen peroxide, but high levels of dissolved

oxygen (D.O.) can be toxic to microorganisms.


Hazardous Materials


Hydrophilic

Having an affinity for water, or capable of dissolving in water; soluble or miscible in water.

Hydrophobic

1. Tending not to combine with water, or incapable of dissolving in water; insoluble or immiscible in

water. A property exhibited by non-polar organic compounds, including the petroleum hydrocarbons.

2. Having a strong aversion for water.

Hypoxic

A condition of low oxygen concentration, below that considered aerobic.

Ignitable

Capable of burning or causing a fire.

Incident Command Post

A facility located at a safe distance from an emergency site, where the incident commander, key staff, and

technical representatives can make decisions and deploy emergency manpower and equipment.

Incident Command System (ICS)

The organizational arrangement wherein one person, normally the Fire Chief of the impacted district, is in

charge of an integrated, comprehensive emergency response organization and the emergency incident site,

backed by an Emergency Operations Center staff with resources, information, and advice.

Incident Commander

The person in charge of on-scene coordination of a response to an incident, usually a senior officer in a fire

department.

Incineration

A treatment technology involving destruction of waste by controlled burning at high temperatures, e.g.,

burning sludge to remove the water and reduce the remaining residues to a safe, non-burnable ash that can be

disposed of safely on land, in some waters, or in underground locations.

Incinerator

A furnace for burning waste under controlled conditions.

Incompatible Waste

A waste unsuitable for mixing with another waste or material because it may react to form a hazard.


Hazardous Materials


Indicator

1. In biology, an organism, species, or community whose characteristics show the presence of specific

environmental conditions.

2. In chemistry, a substance that shows a visible change, usually of color, at a desired point in a chemical

reaction.

3. A device that indicates the result of a measurement, e.g., a pressure gauge or a moveable scale.

Indigenous

Living or occurring naturally in a specific area or environment; native.

Infectious Waste

Hazardous waste with infectious characteristics, including --contaminated animal waste; human blood and

blood products; isolation waste, pathological waste; and discarded sharps (needles, scalpels or broken medical

instruments.)

Infiltration Rate

The quantity of water than can enter the soil in a specified time interval.

Insecticide

A pesticide compound specifically used to kill or prevent the growth of insects.

Ion

An electrically charged atom that can be drawn from waste water during electrodialysis.

Ionizing Radiation

Radiation that can strip electrons from atoms, i.e., alpha, beta, and gamma radiation.

Irradiation

Exposure to radiation of wavelengths shorter than those of visible light (gamma, x-ray, or ultraviolet), for

medical purposes, to sterilize milk or other foodstuffs, or to induce polymerization of monomers or

vulcanization of rubber.

Irritant

1. A substance that can cause irritation of the skin, eyes, or respiratory system. Effects may be acute from

a single high level exposure, or chronic from repeated low-level exposures to such compounds as

chlorine, nitrogen dioxide, and nitric acid.

2. Chemicals which inflame living tissue by chemical action at the site of contact, causing pain or

swelling.


Hazardous Materials


Isotope

A variation of an element that has the same atomic number of protons but a different weight because of the

number of neutrons. Various isotopes of the same element may have different radioactive behaviors, some are

highly unstable.

Kinetic Energy

Energy possessed by a moving body of water as a result of its motion.

Landfills

1. Sanitary landfills are disposal sites for non-hazardous solid wastes spread in layers, compacted to the

smallest practical volume, and covered by material applied at the end of each operating day.

2. Secure chemical landfills are disposal sites for hazardous waste, selected and designed to minimize the

chance of release of hazardous substances into the environment.

Lead (Pb)

A heavy metal that is hazardous to health if breathed or swallowed. Its use in gasoline, paints, and plumbing

compounds has been sharply restricted or eliminated by federal laws and regulations. (See -- heavy metals.)

Listed Waste

Wastes listed as hazardous under RCRA but which have not been subjected to the Toxic Characteristics

Listing Process because the dangers they present are considered self-evident.

Management Plan

Under the Asbestos Hazard Emergency Response Act (AHERA), a document that each Local Education

Agency is required to prepare, describing all activities planned and undertaken by a school to comply with

AHERA regulations, including building inspections to identify asbestos-containing materials, response

actions, and operations and maintenance programs to minimize the risk of exposure.

Material Safety Data Sheet (MSDS)

A compilation of information required under the OSHA Communication Standard on the identity of

hazardous chemicals, health, and physical hazards, exposure limits, and precautions. Section 311 of SARA

requires facilities to submit MSDSs under certain circumstances.

Medical Waste

Any solid waste generated in the diagnosis, treatment, or immunization of human beings or animals, in

research pertaining thereto, or in the production or testing of biologicals, excluding hazardous waste identified

or listed under 40 CFR Part 261 or any household waste as defined in 40 CFR Sub-section 261.4 (b)(1)).

Melting Point

The temperature at which a solid material changes to a liquid. Solid materials with low melting points should

not be stored in hot areas.


Hazardous Materials


Meniscus

The curved top of a column of liquid in a small tube.

Mercury

A heavy metal that can accumulate in the environment and is highly toxic if breathed or swallowed. (See --

heavy metals.)

Metabolism

A term that encompasses all of the diverse reactions by which a cell processes food material to obtain energy

and the compounds from which new cell components are made.

Methane

A colorless, nonpoisonous, flammable gas created by anaerobic decomposition of organic compounds.

Methanol

An alcohol that can be used as an alternative fuel or as a gasoline additive. It is less volatile than gasoline;

when blended with gasoline it lowers the carbon monoxide emissions but increases hydrocarbon emissions.

Used as pure fuel, its emissions are less ozone-forming that those from gasoline.

Microbial Growth

The activity and growth of microorganisms such as bacteria, algae, diatoms, plankton, and fungi.

Microorganisms

Microscopic organisms including bacteria, protozoans, yeast, fungi, mold, viruses, and algae.

Minimal Risk Level (MRL)

An MRL is defined as an estimate of daily human exposure to a substance that is likely to be without an

appreciable risk of adverse effects (noncancer) over a specified duration of exposure. MRLs are derived when

reliable and sufficient data exist to identify the target organ(s) of effect or the most sensitive health effect(s)

for a specific duration via a given route of exposure. MRLs are based on noncancer health effects only. MRLs

can be derived for acute, intermediate, and chronic duration exposures by the inhalation and oral routes.

Molecular Weight

The amount of mass in one mole of molecules of a substance as determined by summing the masses of the

individual atoms which make up the molecule.

Molecule

The smallest division of a compound that still retains or exhibits all the properties of the substance.


Hazardous Materials


Mutagen/ Mutagenicity

An agent that causes a permanent genetic change in a cell other than that which occurs during normal genetic

recombination. Mutagenicity is the capacity of a chemical or physical agent to cause such permanent

alternation.

Necrosis

Death of plant or animal cells or tissues. In plants, necrosis can discolor stems or leaves or kill a plant

entirely.

Nitrate

Plant nutrient and inorganic fertilizer that enters water supply sources from septic systems, animal feed lots,

agricultural fertilizers, manure, industrial waste waters, sanitary landfills and garbage dumps.

Nitric Oxide (NO)

A gas formed by combustion under high temperature and high pressure in an internal combustion engine;

changes into nitrogen dioxide in the ambient air and contributes to photochemical smog.

Nitrite

1. An intermediate in the process of nitrification.

2. Nitrous oxide salts used in food preservation

Nitrogen Dioxide (NO2)

The result of nitric oxide combining with oxygen in the atmosphere; major component of photochemical

smog.

Nitrogen Oxide (NOx)

Product of combustion from transportation and stationary sources and a major contributor to the formation of

ozone in the troposphere and to acid deposition.

Non-potable

Water that is unsafe or unpalatable to drink because in contains objectionable pollution, contamination,

minerals, or infective agents.

Nutrient

1. Any substance assimilated by living things that promotes growth. The term is generally applied to

nitrogen and phosphorus in wastewater, but is also applied to other essential and trace elements.

2. Major elements (e.g., nitrogen and phosphorus) and trace elements (including sulfur, potassium,

calcium, and magnesium) that are essential for the growth of organisms.


Hazardous Materials


Oil Spill

An accidental or intentional discharge of oil which reaches bodies of water. Can be controlled by chemical

dispersion, combustion, mechanical containment, and/or adsorption. Spills from tanks and pipelines can also

occur away from water bodies, contaminating the soil, getting into sewer systems and threatening

underground water sources.

Opacity

The amount of light obscured by particulate pollution in the air; clear window glass has zero opacity, a brick

wall is 100 percent opaque. Opacity is an indicator of changes in performance of particulate control systems.

Operation and Maintenance

1. Activities conducted after a Superfund site action is completed to ensure that the action is effective.

2. Actions taken after construction to assure that facilities constructed to treat waste water will be

properly operated and maintained to achieve normative efficiency levels and prescribed effluent

limitations in an optimum manner.

3. On-going asbestos management plan in a school or other public building, including regular

inspections, various methods of maintaining asbestos in place, and removal when necessary.

Organic

1. Referring to or derived from living organisms.

2. In chemistry, any compound containing carbon.

3. Animal or plant-produced substances containing mainly carbon, hydrogen, nitrogen, and oxygen.

Organic Compound

Chemicals that contain carbon. Volatile organic compounds vaporize at room temperature and pressure. They

are found in many indoor sources, including many common household products and building materials.

Organic Matter

Carbonaceous waste contained in plant or animal matter and originating from domestic or industrial sources.

Organism

Any form of animal or plant life.

OSHA

The Occupational Safety and Health Administration, part of the Department of Labor.

Osmosis

The passage of a liquid from a weak solution to a more concentrate solution across a semipermeable

membrane that allows passage of the solvent (water) but not the dissolved solids.


Hazardous Materials


Oxidant

A substance containing oxygen that reacts chemically in air to produce a new substance; the primary

ingredient of photochemical smog.

Oxidation

The addition of oxygen that breaks down organic waste or chemicals such as cyanides, phenols, and organic

sulfur compounds in sewage by bacterial and chemical means.

Ozone (O3)

Found in two layers of the atmosphere, the stratosphere and the troposphere. In the stratosphere (the

atmospheric layer 7 to 10 miles or more above the earth's surface) ozone is a natural form of oxygen that

provides a protective layer shielding the earth from ultraviolet radiation.In the troposphere (the layer

extending up 7 to 10 miles from the earth's surface), ozone is a chemical oxidant and major component of

photochemical smog. It can seriously impair the respiratory system and is one of the most widespread of all

the criteria pollutants for which the Clean Air Act required EPA to set standards. Ozone in the troposphere is

produced through complex chemical reactions of nitrogen oxides, which are among the primary pollutants

emitted by combustion sources; hydrocarbons, released into the atmosphere through the combustion, handling

and processing of petroleum products; and sunlight.

Packaging

The assembly of one or more containers and any other components necessary to assure minimum compliance

with a program's storage and shipment packaging requirements. Also, the containers, etc., involved.

Pandemic

Widespread throughout an area, nation or the world.

Particle Count

Results of a microscopic examination of treated water with a special "particle counter" that classifies

suspended particles by number and size.

Particulates

1. Fine liquid or solid particles such as dust, smoke, mist, fumes, or smog found in air or emissions.

2. Very small solid suspended in water. They vary in size, shape, density, and electrical charge, can be

gathered together by coagulation and flocculation.

Pathogens

Microorganisms that can cause disease in other organisms or in humans, animals and plants (e.g., bacteria,

viruses, or parasites) found in sewage, in runoff from farms or rural areas populated with domestic and wild

animals, and in water used for swimming. Fish and shellfish contaminated by pathogens, or the contaminated

water itself, can cause serious illness.


Hazardous Materials


PEL

Permissible Exposure Limits set by OSHA as a guide to acceptable levels of chemical exposure.

Permeability

1. A qualitative description of the relative ease with which rock, soil, or sediment will transmit a fluid

(liquid or gas). Often used as a synonym for hydraulic conductivity or coefficient of permeability.

2. The rate at which liquids pass through soil or other materials in a specified direction.

Permissible Dose

The dose of a chemical that may be received by an individual without the expectation of a significantly

harmful result.

Permit

An authorization, license, or equivalent control document issued by EPA or an approved state agency to

implement the requirements of an environmental regulation; e.g., a permit to operate a wastewater treatment

plant or to operate a facility that may generate harmful emissions.

Pesticide

Substances or mixture there of intended for preventing, destroying, repelling, or mitigating any pest. Also, any

substance or mixture intended for use as a plant regulator, defoliant, or desiccant.

pH

The pH is a measure of how acidic or caustic a chemical is, based on a scale of 1 to 14. A pH of 1 means the

chemical is very acidic. Pure water has a pH of 7. A pH of 14 means the chemical is very caustic. Both acidic

and caustic substances are dangerous to skin and other valuable surfaces.

Phenols

Organic compounds that are byproducts of petroleum refining, tanning, and textile, dye, and resin

manufacturing. Low concentrations cause taste and odor problems in water; higher concentrations can kill

aquatic life and humans.

Phosphates

Certain chemical compounds containing phosphorus.

Phosphorus

An essential chemical food element that can contribute to the eutrophication of lakes and other water bodies.

Increased phosphorus levels result from discharge of phosphorus-containing materials into surface waters.


Hazardous Materials


Photosynthesis

The manufacture by plants of carbohydrates and oxygen from carbon dioxide mediated by chlorophyll in the

presence of sunlight.

Physical and Chemical Treatment

Processes generally used in large-scale wastewater treatment facilities. Physical processes may include air-

stripping or filtration. Chemical treatment includes coagulation, chlorination, or ozonation. The term can also

refer to treatment of toxic materials in surface and ground waters, oil spills, and some methods of dealing with

hazardous materials on or in the ground.

Phytotoxic

Harmful to plants.

Pilot Test

1. Operation of a small-scale version of a larger system to gain information relating to the anticipated

performance of the larger system. Pilot test results are typically used to design and optimize the larger

system.

2. Testing a cleanup technology under actual site conditions to identify potential problems prior to full-

scale implementation.

Plastics

Non-metallic chemoreactive compounds molded into rigid or pliable construction materials, fabrics, etc.

Plutonium

A radioactive metallic element chemically similar to uranium.

Poison

A chemical that, in relatively small amounts, is able to produce injury by chemical action when it comes in

contact with a susceptible tissue.

Pollen

The fertilizing element of flowering plants; background air pollutant.

Pollutant

Generally, any substance introduced into the environment that adversely affects the usefulness of a resource.

Pollution

Generally, the presence of matter or energy whose nature, location, or quantity produces undesired

environmental effects. Under the Clean Water Act, for example, the term is defined as the manmade or man-

induced alteration of the physical, biological, chemical, and radiological integrity of water.


Hazardous Materials


Polonium

A radioactive element that occurs in pitchblende and other uraniumcontaining ores.

Polymer

Basic molecular ingredients in plastic.

Population at Risk

A population subgroup that is more likely to be exposed to a chemical, or is more sensitive to the chemical,

than is the general population.

Potable Water

Water that is safe for drinking and cooking.

Precipitation

Removal of hazardous solids from liquid waste to permit safe disposal; removal of particles from airborne

emissions.

Propellant

Liquid in a self-pressurized pesticide product that expels the active ingredient from its container.

Proposed Plan

A plan for a site cleanup that is available to the public for comment.

Protocol

A series of formal steps for conducting a test.

Protozoa

Single-celled, eukaryotic microorganisms without cell walls. Most protozoa are free-living although many are

parasitic. The majority of protozoa are aerobic or facultative anaerobic heterotrophs.

Public Health Advisory

A statement by ATSDR containing a finding that a release of hazardous substances poses a significant risk to

human health and recommending measures to be taken to reduce exposure and eliminate or substantially

mitigate the significant risk to human health.

Public Health Hazard

Sites that pose a public health hazard as the result of long-term exposures to hazardous substances.


Hazardous Materials


Radiation

Transmission of energy through space or any medium. Also known as radiant energy.

Radioisotopes

Chemical variants of an element with potentially oncogenic, teratogenic, and mutagenic effects on the human

body.

Radon

A colorless naturally occurring, radioactive, inert gas formed by radioactive decay of radium atoms in soil or

rocks.

RCRA

The Resource Conservation and Recovery Act (of 1976). A Federal statute which establishes a framework for

proper management and disposal of all wastes. Generation, transportation, storage, treatment, and disposal of

hazardous wastes are all regulated under this Act.

Reagent

A substance or solution used in a chemical reaction, especially those used in laboratory work to detect,

measure, or produce other substances.

Reasonable Maximum Exposure

The maximum exposure reasonably expected to occur in a population.

Recycle/Reuse

Minimizing waste generation by recovering and reprocessing usable products that might otherwise become

waste (.i.e. recycling of aluminum cans, paper, and bottles, etc.).

Regulated Medical Waste

Under the Medical Waste Tracking Act of 1988, any solid waste generated in the diagnosis, treatment, or

immunization of human beings or animals, in research pertaining thereto, or in the production or testing of

biologicals. Included are cultures and stocks of infectious agents; human blood and blood products; human

pathological body wastes from surgery and autopsy; contaminated animal carcasses from medical research;

waste from patients with communicable diseases; and all used sharp implements, such as needles and scalpels,

etc., and certain unused sharps. (See; treated medical waste; untreated medical waste; destroyed medical

waste.)


Hazardous Materials


Remediation

1. Cleanup or other methods used to remove or contain a toxic spill or hazardous materials from a

Superfund site;

2. for the Asbestos Hazard Emergency Response program, abatement methods including evaluation,

repair, enclosure, encapsulation, or removal of greater than 3 linear feet or square feet of asbestos-

containing materials from a building.

Residue

The dry solids remaining after the evaporation of a sample of water or sludge.

Risk

A measure of the probability that damage to life, health, property, and/or the environment will occur as a

result of a given hazard.

Risk Assessment

Broadly defined as the scientific activity of evaluating the toxic properties of a chemical and the conditions of

human exposure to it, with the objective of determining the probability that exposed humans will beadversely

affected. Its four main components are:

1. Hazard Identification -- Does the agent cause the effect?

2. Dose-Response Assessment -- What is the relationship between the dose and its incidence in human

beings?

3. Exposure Assessment -- What exposures are experienced or anticipated, and under what conditions?

4. Risk Characterization - The total analysis producing an estimate of the incidence of the adverse effect

in a given population.

Risk Factor

Characteristic (e.g., race, sex, age, obesity) or variable (e.g., smoking, occupational exposure level) associated

with increased probability of a toxic effect.

Risk Management

The process of evaluating and selecting alternative regulatory and non-regulatory responses to risk. The

selection process necessarily requires the consideration of legal, economic, and behavioral factors.

Route of Exposure

The avenue by which a chemical comes into contact with an organism (e.g., inhalation, ingestion, dermal

contact, injection.)

Salts

Minerals that water picks up as it passes through the air, over and under the ground, or from households and

industry.


Hazardous Materials


Septic System

An onsite system designed to treat and dispose of domestic sewage. A typical septic system consists of a tank

that receives waste from a residence or business and a system of tile lines or a pit for disposal of the liquid

effluent (sludge) that remains after decomposition of the solids by bacteria in the tank and must be pumped

out periodically.

Sharps

Hypodermic needles, syringes (with or without the attached needle) pasteur pipettes, scalpel blades, blood

vials, needles with attached tubing, and culture dishes used in animal or human patient care or treatment, or in

medical, research or industrial laboratories. Also included are other types of broken or unbroken glassware

that were in contact with infectious agents, such as used slides and cover slips, and unused hypodermic and

suture needles, syringes, and scalpel blades.

Signal Words

The words used on a pesticide label-Danger, Warning, Caution-to indicate level of toxicity.

Solid Waste

Non-liquid, non-soluble materials ranging from municipal garbage to industrial wastes that contain complex

and sometimes hazardous substances. Solid wastes also include sewage sludge, agricultural refuse, demolition

wastes, and mining residues. Technically, solid waste also refers to liquids and gases in containers.

Solubility

The amount of mass of a compound that will dissolve in a unit volume of solution.

Specific Gravity

A comparison of the weight of the chemical to the weight of an equal volume of water. Chemicals with a

specific gravity of less than 1 are lighter than water, while a specific gravity of more than 1 means the

chemical is heavier than water. Most flammable liquids are lighter than water.

Sterilization

The removal or destruction of all microorganisms, including pathogenic and other bacteria, vegetative forms

and spores.

Sulfur Dioxide (SO2)

A pungent, colorless, gaseous pollutant formed primarily by the combustion of fossil fuels.

Synergism

An interaction of two or more chemicals which results in an effect that is greater than the sum of their effects

taken independently.


Hazardous Materials


Teratogen

A material that produces a physical defect in a developing embryo.

Threshold

The lowest dose of a chemical at which a specific measurable effect is observed. Below this dose, the effect is

not observed.

Threshold Level

Time-weighted average pollutant concentration values, exposure beyond which is likely to adversely affect

human health. (See - environmental exposure.)

Threshold Limit Value (TLV)

The concentration of an airborne substance that an average person can be repeatedly exposed to without

adverse effects. TLVs may be expressed in three ways –

TLV-TWA-Time weighted average, based on an allowable exposure averaged over a normal 8-hour

workday or 40-hour workweek;

TLV-STEL-Short-term exposure limit or maximum concentration for a brief specified period of time,

depending on a specific chemical (TWA must still be met); and

TLV-C- Ceiling Exposure Limit or maximum exposure concentration not to be exceeded under any

circumstances. (TWA must still be met.)

TLV

Threshold Limit Values, which are the calculated airborne concentrations of a substance to which all workers

could be repeatedly exposed eight hours a day without adverse effects.

Toxic Chemical

Any chemical listed in EPA rules as "Toxic Chemicals Subject to Section 313 of the Emergency Planning and

Community Right-to-Know Act of 1986."

Toxic Substance

A chemical or mixture that may present an unreasonable risk of injury to health or the environment.

Toxic Waste

A waste that can produce injury if inhaled, swallowed, or absorbed through the skin.

Toxicity

The degree of danger posed by a substance to animal or plant life.


Hazardous Materials


Toxicology

The study of the adverse effects of chemicals on biological systems, and the assessment of the probability of

their occurrence.

Treatment

1. Any method, technique, or process designed to remove solids and/or pollutants from solid waste, waste

streams, effluents, and air emissions.

2. Methods used to change the biological character or composition of any regulated medical waste so as to

substantially reduce or eliminate its potential for causing disease.

Ultraviolet Rays

Radiation from the sun that can be useful or potentially harmful. UV rays from one part of the spectrum (UV-

A) enhance plant life and are useful in some medical and dental procedures; UV rays from other parts of the

spectrum (UV-B) can cause skin cancer or other tissue damage. The ozone layer in the atmosphere partly

shields us from ultraviolet rays reaching the earth's surface.

Unsaturated

The characteristic of a carbon atom in a hydrocarbon molecule that shares a double bond with another carbon

atom.

Vapor Density

The measure of the heaviness of a chemical’s vapor as compared to the weight of a similar amount of air. A

vapor density of 1.0 is equal to air. Vapors that are heavier than air may build up in low-lying areas, such as

along floors, in sewers, or in elevator shafts. Vapors that are lighter than air rise and may collect near the

ceiling.

Ventilation/ Suction

The act of admitting fresh air into a space in order to replace stale or contaminated air; achieved by blowing

air into the space. Similarly, suction represents the admission of fresh air into an interior space by lowering

the pressure outside of the space, thereby drawing the contaminated air outward.

Viscosity

A measure of the internal friction of a fluid that provides resistance to shear within the fluid. The greater the

forces of internal friction (i.e. the greater the viscosity), the less easily the fluid will flow.

Volatile

Any substance that evaporates readily.

Volatile Liquids

Liquids which easily vaporize or evaporate at room temperature.


Hazardous Materials


Waste

1. Unwanted materials left over from a manufacturing process.

2. Refuse from places of human or animal habitation.

hazardous materials glossary - uab...alkali the hydroxides and carbonates of the alkali metals and...

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